Description

This invention relates to a location device, a network appliance and a
network. An example of such a location device can be found in for example US-A-5910776.

Background of the Invention

[0002]

In conventional computer networks where a plurality of appliances are
connected via the network, each appliance has a network address which enables
information to be routed to it over the network. The network address has no
correlation with the physical location of the appliance.

[0003]

Providing network appliances with location awareness has many
potential applications. These range from relatively simple applications such as
inventory control so that for example an office manager would be able to
identify the presence of each piece of equipment in an office or building, to
more advanced applications such as providing information tailored to a user's
physical location, such as the Hewlett Packard Cooltown project which aims to
produce a connection between the physical and virtual worlds. A service
location method for locating devices on a network could include the physical
location of a network appliance as part of a search parameter.

[0004]

A number of techniques for providing location awareness for networked
devices have been proposed. For example, each device can be manually
programmed with location information or provided with the location using a
network bootstrap protocol such as BOOTP. However, when a device's
location is changed, the change must be manually recorded in the device or the
configuration database. Radio frequency identification (RFID) is a technique in
which transducers, commonly known as tags, carry data and suitable readers
can read a tag to retrieve the data. The data held in the tag may comprise any
information as desired, and the distance at which a tag can be read depends in
part on the power available to the reader and may be adapted to match the
particular application required. To provide location awareness for a network
appliance, it might be envisaged that, for example, a physical location may be
provided with a tag and network appliances supplied with a reader to read the
location information contained in the tag. Alternatively, a network appliance
could be provided with a tag and a suitably powerful reader could be located in
each physical location to read the tag of a network appliance placed in the that
location.

[0005]

A further system which uses radio frequency transmissions and which
may be adapted to provide location information is Bluetooth, a protocol
whereby devices may communicate over an ad hoc local network using radio
communications. It is known to provide a "beacon" which transmits a location
signal using a Bluetooth link to all devices in its range. A related technique is
infra red beacons which transmit location information over an infrared link to
devices equipped with suitable detectors, for example using the IrDA protocol.

[0006]

These techniques are however disadvantageous in providing location
awareness for network appliances in that they each require a relative complex
infrastructure to provide location signals.

[0007]

A simple protocol for enabling devices to communicate via a mains
electricity power supply network in a building is the X10 protocol. X10
provides a robust system for signalling between devices by superimposing a
high-frequency modulation on the relatively low frequency alternating current
mains supply. Using X10, a control unit is connected to a device to be
controlled, for example a light switch or power outlet and has an address set to
one of 256 addresses using a manually settable switch. The control unit only
responds to messages sent to that address. It is a feature of the X10 protocol
that several control units can be provided with the same address such for
example, a number of lights may be turned on or off with a single message.

[0008]

The X10 protocol is disadvantageous in that an X10 control unit does
not provide its address to a device connected to it, nor is the address necessarily
correlated to the physical location.

[0009]

An aim of the invention is to provide a new or improved location device
for a network appliance which overcomes or reduces one or more of the above
disadvantages.

Summary of the Invention

[0010]

According to a first aspect of the invention, we provide a location device
connectable to a mains power outlet of a mains power system, the location
device being connectable to a power connection of a network appliance, the
location device being operable to transmit location information to the network
appliance via said power connection.

[0011]

According to this invention, a low cost location device is provided in a
power socket which can transmit location information to a network appliance
which is plugged into that socket.

[0012]

The location device address information may comprise an identification
number corresponding to the location device.

[0013]

The location device address information may be transmitted periodically
by the location device over the power connection.

[0014]

The location device according may be operable to receive a location
request from the network appliance and transmit location information in
response to the location request.

[0015]

The location device may be operable to detect the power connection of a
network appliance and transmit location information when a power connection
is detected.

[0016]

The location device may further comprise a filter whereby the location
information is not transmitted over the mains power system.

[0017]

According to a second aspect of the invention, we provide a network
appliance which comprises a power connection connectable to a mains power
supply, the network appliance further comprising a receiver module operable to
receive location information from a location device via the power connection.

[0018]

The network appliance may comprise a network connection whereby the
network appliance is operable to transmit the location information to a network
via the network connection.

[0019]

According to a third aspect of the invention, we provide a network
comprising a server according to the second aspect of the invention, a location
device according to the first aspect of the invention and a network appliance
wherein the network appliance is operable to transmit the location information
received from the location device to the server via the network connection.

[0020]

The network server may comprise location device information whereby
the server can read the location information and obtain a corresponding
physical location for the network appliance.

[0021]

The location device information may comprise a lookup table where the
location information comprises an identification number and the lookup table
comprises physical location information corresponding to each identification
number.

Description of the drawings

[0022]

An embodiment of the invention will now be described by way of
example only with reference to the accompanying drawings wherein;

Figure 1 is a diagrammatic illustration of a building provided with a
network embodying the present invention,

Figure 2 is a diagrammatic illustration of a location device and a
network appliance embodying the present invention.

Detailed Description of the preferred embodiments

[0023]

Referring now to Figure 1, a plan of a building or part of a building is
generally shown at 10. The building 10 is provided with a electrical mains
power system comprising a mains power supply circuit 11 of conventional type
which is provided with a plurality of mains power outlets comprising sockets
12 distributed throughout the building 10 in conventional manner. A plurality
of network appliances 13 are located within the building, in the present
example purely by way of illustration comprising personal computers 13a and
13b, printers 14a and 14b, a scanner 15 and a server 16. The network
appliances 13 are interconnected by a suitable network 17. Each network
appliance is connected in conventional manner by a power cable 18 to a mains
socket 12 of the main power circuit 11.

[0024]

The network 17 of Figure 1 is purely a diagrammatic illustration, and
may comprise an electrical connection such as Ethernet or FireWire, a radio
network such as Bluetooth or 802.11 or any other appropriate network as
desired. Further, although Figure 1 shows a network located within a building
or part of a building, it will be clear that the present invention may be used with
a much more widely dispersed network or even with devices interconnected via
the internet.

[0025]

Referring to Figure 2, a socket 12 is shown in diagrammatic form with a
live line 20 and a neutral line 21 connected to the mains power supply circuit
11 in conventional manner. The location device 19 comprises an appropriate
number of pins, in this example two, to engage the socket 12 to make an
appropriate electrical connection. The location device 19 similarly comprises a
live line 23a and a neutral line 23b in conventional manner connected to pins
22 to engage the socket 12, and is provided with a suitable socket to receive a
power connection comprising a plug 24 provided with pins 25 connected to a
power line 18 for a network appliance 13. The location device 19 provides a
through connection between the corresponding pins 25 and 22, such that the
network appliance 13 is able to draw power from the mains power supply
circuit via the socket 12 in conventional manner.

[0026]

The location device 19 is provided with a location transmitter 26 and in
this example a filter 27. The location transmitter 26 comprises a memory 26a
in which location information is held, and is operable to modulate the mains
alternating current such a way as to superimpose a location information signal
encoding the location information on the alternating current. The filter 27 is
arranged such that the location information signal superimposed on the
alternating current is not transmitted into the mains power supply circuit 11.

[0027]

Provided in the network appliance 13 is a power supply unit (PSU) 28 of
conventional type which is connected to the plug 24 and pins 25 to receive
mains current via the power cable 18 and transform or otherwise convert into
the mains current electrical power for supply to the components of the network
appliance 13. The modulation of the mains current by the location device 19 is
of such a frequency and/or magnitude that the output of the PSU 28 is not
affected. In addition or alternatively, the PSU 28 may be provided with a filter
to remove the modulation.

[0028]

The network appliance 13 in conventional manner has a network card 29
to provide a network connection 30 and a suitable mother board 31, in this
example interconnected by a conventional bus 32. The network appliance 13 is
further provided with a reader 33 which is able to detect the location
information signal superimposed on the mains alternating current by the
location device 19. The reader 33 then transmits the information via the bus, to
the network card 29 or the mother board 31 or elsewhere as desired.

[0029]

The invention thus provides a relatively inexpensive and simple method
of providing automatic location detection for a network appliance. A location
device 19 is provided with location information and plugged into a socket 12.
A location device 19 may of course be provided integrally with the mains
socket 12 if desired. When a network appliance 13 is plugged into a socket 12
comprising a location device 19, the location device will transmit location
information via the power cord 18 on the mains alternating current where it is
read by the reader 33 and made available to the network appliance 13. The
location device 19 may, periodically transmit the location information, or may
transmit the location information in response to an enquiry from the network
appliance 13 transmitted by the reader 33, or may detect power being drawn
from the mains power circuit 11 by a network appliance 13, thus indicating that
a network appliance 13 has been plugged in and the power turned on and
transmit the location information in response.

[0030]

The network appliance 13 then makes the location information available
over the network 17 to other network appliances 13. The location information
may be encoded as desired. For example, the location information may
comprise a unique identification number associated with that location device.
To provide a physical location, the server 16 may have a table which gives a
physical location corresponding to the location information transmitted by each
location device so that the server 16 acts as a name server maintaining the
mapping <socket location-signal, room-name> in a look up table.
Alternatively, all of the network appliances 13 may be provided with such a
look up table. Further alternatively, the location information may actually
encode details of the physical location stored in the store 26a, for example
"room number 3, north west corner". The location information may be in any
format and provided and accessed in any manner as desired. The location
information may be used for any application where physical location
information may be useful.

[0031]

If the network appliance 13 is subsequently moved to a different location
and is plugged into a different socket 12, it will then receive new location
information from the location device 19 connected with that socket, and will be
able to make the new location information available over the network 17. The
device's new physical location is thus made available automatically.

[0032]

The location information signal may be superimposed on and read from
the alternating mains current using any encoding and transmission protocol as
desired, for example the same technique as the X10 protocol or any other
suitably robust communication protocol and any appropriate electronic
implementation as necessary.

[0033]

It might be envisaged that the network 17 comprises a power-line
network which uses the mains power supply circuit 11 as a communications
network. In such circumstances the filter 27 may be omitted, or alternatively
the frequency at which the location information is transmitted by the location
device 19 to the network appliance 13 and the frequency at which the network
appliance 13 transmits the information over the power line network may be
different and the filter 27 may be selected to block the location information
signal but not network transmissions to and from the main power supply circuit
11.

[0034]

In the present specification "comprises" means "includes or consists of
and "comprising" means "including or consisting of'.

[0035]

The features disclosed in the foregoing description, or the following
claims, or the accompanying drawings, expressed in their specific forms or in
terms of a means for performing the disclosed function, or a method or process
for attaining the disclosed result, as appropriate, may, separately, or in any
combination of such features, be utilised for realising the invention in diverse
forms thereof.

Claims (12)

A location device (19) connectable to a power outlet (12) of a mains
power system, the location device (19) being connectable to a power
connection of a network appliance (13), characterised in that the location device (19) being operable
to transmit location information to the network appliance (13) via said power
connection.

A location device (19) according to claim 1 wherein the location
information comprises an identification number corresponding to the location
device (19).

A location device (19) according to any one of the preceding claims
wherein the location information is transmitted periodically by the location
device (19) over the power connection.

A location device according to any one of the preceding claims wherein
the location device (19) is operable to receive a location request from the
network appliance (13) and transmit location information in response to the
location request.

A location device (19) according to any one of the preceding claims
operable to detect the power connection of a network appliance (13) and
transmit location information when a power connection is detected.

A location device (19) according to any one of the preceding claims
further comprising a filter (27) whereby the location information is not
transmitted over the mains power system.

A network appliance (13) comprising a power connection connectable to
a mains power system,
characterised in that the network appliance (13) further comprising a reader
(33) operable to receive location information from a location device (19) via
the power connection.

A network appliance (13) according to claim 8 comprising a network
connection (30) whereby the network appliance (13) is operable to transmit the
location information to another network appliance (13) via the network
connection (30).

A network comprising a server (16), a location device (19) according to
any one of claims 1 to 7 and a network appliance (13) according to claim 8 or
claim 9 wherein the network appliance (13) is connected to the location device
(19) and is operable to transmit the location information received from the
location device (19) to the server (16) via the network connection (30).

A network according to claim 10 wherein the server (16) comprises
location device information whereby the server (16) can read the location
information received from the network appliance (13) and obtain a
corresponding physical location for the network appliance (13).

A network according to claim 11 wherein the location device
information comprises a lookup table where the location information comprises
an identification number and the lookup table comprises physical location
information corresponding to each identification number.